3.9 v8 rebuild

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beebe

New Member
Posts
71
Location
Beebe, Arkansas, USA
Hello,
I recently bought a non running '95 discovery, v8 automatic for cheap. It had the engine partially disassembled, due to it having an overheating problem. So I took it out and stripped it down to the block. Two pistons had small chunks missing. I took the block to a machine shop, and they honed the cylinders and he called me back and said 4 of the cylinders are oval.

So I found some +20 thou oversize pistons on ebay, from RPI Engineering. He's going to bore out the cylinders.

These are the pistons Land Rover V8 3.9 Pistons Kit Car Morgan MG TVR Marcos - eBay (item 190357560029 end time Dec-17-09 01:22:53 PST)

Was this the right thing to do? Are those liners thick enough to accommodate a rebore? Especially since these pistons have a higher compression ratio than the standard ones?

Cheers,
Roger

P.S. Here is the Discovery http://g5i.net/pictures/engineout.jpg
 
Hi Rodger,

The discovery's V8 is a rover V8, and them parts are designed for a rover V8, and RPI are a reputable company that specialize in rover V8 parts (and bespoke builds) so yes it was the right thing to do - the liners are easy thick enough - and - it gets the disco back on the road with a nice reconditioned engine - that you can proudly say that you re-built to people.

Them pistons aren't doing anything to the compression, as the 3.9 in the discovery is the 174bhp high compression engine, i.e. 9.35 : 1 compression ratio.
 
the 3.9 is strong in most cases.its just wot v8 rovers do,wack a merc v8 init if ya like it that much.

Seems you've done one or two more posts on the forum than me, so I probably should be listening to you, but I'm still confused. An engine, which has done 160k can be rebuilt but then can't be relied upon for anything further than about 20k?

I thought rebuilt engines were often better than new engines because the block is seasoned. You're less likely to get warped heads etc. because stuff has warped as much as it's going to and then has been machined back to within tolerance.
 
Seems you've done one or two more posts on the forum than me, so I probably should be listening to you, but I'm still confused. An engine, which has done 160k can be rebuilt but then can't be relied upon for anything further than about 20k?

I thought rebuilt engines were often better than new engines because the block is seasoned. You're less likely to get warped heads etc. because stuff has warped as much as it's going to and then has been machined back to within tolerance.

Yes but rover v8's arnt like normal engines, they are ****e!:D

I know, I got one:doh:
 
Yes but rover v8's arnt like normal engines, they are ****e!:D

I know, I got one:doh:
not true but yes fett.

I do have a good one.A 4.0 with carbs on.tis sweet.It has done 180k miles on LPG after being rebuilt and is still good.

most engines are ****e.some are exellent but middle ground is rare.UIF you have a good one it will live long if not you will be very broke and drinking ethanol...
 
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